/*
 * LensKit, an open-source toolkit for recommender systems.
 * Copyright 2014-2017 LensKit contributors (see CONTRIBUTORS.md)
 * Copyright 2010-2014 Regents of the University of Minnesota
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package org.lenskit.util.io;

import javax.annotation.WillCloseWhenClosed;

import com.google.common.base.Predicate;

/**
 * A wrapper stream that filters its underlying stream.
 * @param <T> The stream's element type.
 */
class FilteredObjectStream<T> extends AbstractObjectStream<T> {
    private final ObjectStream<T> delegate;
    private final Predicate<? super T> filter;

    /**
     * Construct a new filtered stream.
     * @param cur The underlying stream.
     * @param filt The filter.
     */
    public FilteredObjectStream(@WillCloseWhenClosed ObjectStream<T> cur, Predicate<? super T> filt) {
        super();
        delegate = cur;
        filter = filt;
    }

    @Override
    public void close() {
        delegate.close();
    }

    @Override
    public T readObject() {
        T obj = delegate.readObject();
        while (obj != null && !filter.apply(obj)) {
            obj = delegate.readObject();
        }

        return obj;
    }
}
